For the second time in a month a Russian spy ship has been spotted near the US coastline, this time off the coast of Georgia.

The Viktor Leonov, a Russian spy vessel outfitted with a variety of high-tech spy equipment and designed to intercept communications signals, was spotted some 20 miles south of the US Naval Submarine Base Kings Bay near the Florida border, a US defense official told CNN. It was heading north.

The ship was docked in Cuba before heading towards the US, said the defense official, who didn't specify when the sighting occurred.

Last month, the US Navy spotted the same ship sailing 30 miles off the coast of Connecticut, the farthest north it had ever ventured, according to a US defense official. The Vishnya-class spy ship also conducted similar patrols in 2014 and 2015.

US jurisdiction extends 12 nautical miles (13.8 miles) from the coast, meaning that the Russian ship was likely in international waters.

This sighting is the latest of several recent encounters involving the Russian military.

In February the USS Porter was sailing in the Black Sea when it had three encounters with Russian aircraft.

The encounters were deemed unsafe and unprofessional because of how close the Russian planes flew to the American destroyer, a senior defense official said last month.

Another defense official said that one of the Russian aircraft, an armed Su-24 attack jet, flew within 200 yards of the Porter at a speed of 500 knots (about 570 mph). It was flying 300 feet above the water, the official said.

The Navy said the aircraft did not cross the deck of the Porter but assessed that the Su-24 was carrying out a "mock attack" on the American ship, according to the official.